X-ray cassette



-F. T. POWERS XLRAY CASSETTE I Filed Nov. 24, 1942' 3 Sheets-Sheet l ATTORNEY Du. 1s, i945. F, T. POWERS 2,391,191

-x-RAY, cass'w Filed Nov. 24, 1942 s sheets-sheet H2' Patented Dec. 18, 1945 UNITED STATES'Y PATENT GFFICE x-RAY cAssET'rE l Frank T. Powers, Glen Cove, N. Y. Application Nbvember 24, 1942, seia1'N0..466,7a'z

(o1. 25o-s6) y Claims.

Thisinvention relates to the radiographic art and relates more particularly to certain new and useful improvements in holders, that k is, oas- Asettes, for holding` the raysensitive medi-um in position during exposure to the sensitizing rays.

Objects and advantages of the invention will be set forth in part hereinafter and in part will be obviousherefrom, or may be learned by practice with the. invention, the same being realized and attained by means of the instrumentalities and combinations pointed out in the appended claims. l f

The invention consists in the novel parts, constructions, arrangements, combinations and improvements herein shown and described.

The accompanying drawings, referred to herein and constituting a part hereof, illustrate one 4embodiment of the invention,andtogether with the description, serve to explain the principles of the invention.

' Of the drawings: Fig. 1 is a vertical section I l of Fig. 2 showing a typical and illustrative X-ray cassette embodying the present invention;

radiography; and, to provide a cassette, for use with a stripy of ray-sensitive material, which will make possible the processing of an exposed portion of the "strip at any time without sacrifice of the unexposed portions of the strip.

Other and further objects of this invention are:V toprovide a cassette, for use with a strip of .ray-sensitive material, which will hold the ray-sensitive material in a more nearly true plane during exposure and will effect a more uniy form contact between the ray-sensitive material and an intensifying screen, kthan has heretofore been obtainable; which'will prevent static electricity such as is frequently generated by unreeling of the strip in the cassette from' harmfully aecting the ray-sensitive material; vand which will permit an operator to sever an exposed portion of the strip at any time and to vremove and process the severed portion, or portions, yof the strip at any convenient time without interference with rcontinued uninterrupted use of the taken along the line cassette in the radiographic operation in which it is being employed.

In accordance with the invention, there is provided a casing which ris opaque to lightv and is also opaque to X-radiation except overa given area which forms a window through which a measured length of a long strip of ray-sensitive material may be exposed to X-radiation.A Means are provided for Vfeeding measured lengths of the strip of ray-sensitive material past said exposure window. Means actuable from without the casing are provided for clamping a measured length of the lm strip within the exposure area so that it will be held therein in intimate contact with an intensifying screen and in a substantially true plane normal to the primary axis of the X-ray beam during the exposure period. For convenience in expression, the ray-sensitive .material is sometimes hereinafter referred to as' lm although it is to be understood that the term film is not used in a restrictive sense, but is intended to include paper base ray-sensitive material as well as the usual cellulose base raysensitive material.

The film feeding means is actuable from the exterior of the casing to unreel measured lengths ofthe film strip from a. fresh film magazine within the casing; to move each measured length of lm into the exposure area so that it may be exposed to X-radiation; and, todeliver the exposed length of film to a. used film magazine.

The film clamping means is actuable from the exterior of the casing and includes a clamping unit, movable into and out of a predetermined clamping position.y The clamping unit is suitably supported within the casing for linear back and forth movement parallel to the axisof the activating beam, the clamping face of the unit being constituted by an intensifying screen of planar contour. Uniform contactof each length 0f film with the intensifying screen, and holding of each said length in a substantially true plane normal to the beam axis during exposure, is obtained by providing the casing, within the exposureA area, with an inwardly concaved flexible wall portion of cylindrical contour in opposition to the clamping unit. Thus, as each length of film strip is clamped between the movable vclamping unit and the Vflexible wall portion, the

intensifying screen and the length of film is firmly held in a true plane normal to the X-ray beam axis.

The operation of unreeling the lm strip from the fresh film magazine and feeding it past said exposure area creates static electricity which, if allowed to accumulate on the lm strip, may discharge with harmful effect to the film emulsion. S called hen tracks in a film negative are a typical manifestation of these electrical effects. Means are, therefore, provided for dissipating any electrical charge acquired by the film strip from any cause, whether frictional or atmospheric. To this end the l-m contacting face of the flexible wall portion is faced with electrically conductive material which is suitably electrically grounded through the casing. The nature of the facing material is preferably such that X-rays in transit therethrough will be filtered so astoimprove the quality of the rays which reach` the film and, a A

priori, the sharpness of the radiographic image which they produce.

It lwill be apparent that as clamping of a length of the lm strip is initiated the clamping pressure would tend to be somewhat localized on the intensifying screen in consequence of the curved contour'of the flexible wall portion. In order to distribute this pressure over the entire area; to

keep the pressure below a value which might injure the screen or lm; and, to accommodate the lscreen to any inequalities in the lm surface or Vthe surface of the flexible wall portion, the intensifying screen is flexibly mounted in its unit 'upon a layer of -compressible resilient material, for example, sponge rubber. intensifying screen by chemical action between Discoloration of the the screen and the rubber is prevented by physically insulating the screen from the rubber by means of a thin sheet ofaluminum or other suitable protective material.

film-'severing means is actuable from the exterior ofthe cassette, the lrequisite actuating mechanism being preferably coupled with that of the clamping unit so that the operations of severing and clamping may be carried out in consequence 4'of movements 0f a single actuating mechanism y in opposite directions.

As each measured length of the l-m strip is moved out of the exposure position it is delivered to a suitable used film magazine adapted to receive and contain the exposed portion of the lfilm strip.` However, if at any time processing of the exposed portion becomes desirable, the exposed portion may be severed from the strip, thus permitting the magazine containing the exposed portion to be removed and replaced so that the radiography may continue uninterruptedly while processing of the exposed portion is carried out. It will be understood that the foregoing general description and the following detailed description as Well lare exemplary and explanatory of the invention but are not restrictive thereof.

Referring now more particularly to the illustrative embodiment of the invention as shown `in Figures l to 3 inclusive, a casing I0 has a planar front wall II apertured to provide an opening I2 of rectangular contour forming an exposure area occupied by a window member -I3 of material which is opaque to light butpermeable to X-rays, such, for example, asy aluminum,

.rear wall I4.

Bakelite or other synthetic resin. The .casing I is formed of material, such as aluminum or wood which provide a light weight structure of satisfactory structural rigidity and strength. Entry of X-rays, except through the window member I3, is prevented by the provisionof a layer of sheet lead (not shown) lining the cassette walls. The thickness will be governed by the type of service for which the cassette is to be used. Lead sheets of a thickness in the order of from to BB-f" are suitable for moderate ray intensities. Access to the interior of the casing I!! is made possible through the provision of a removable Fastening devices, such as the latch members I5 serve to lock and retain the wall I4 in position. The edges of the front wall opening I2 and its window member I3 are each recessed so as to provide light-sealing anges I6 and Ia, respectively which lie in overlapping relation. The window flanges Ia respectively terminate in a bevelled surface Ic which is normally in slightly spaced relation to a complementary bevelled surface IId of the front wall II thereby to permit relative angular movement of the window member and front wall as flexing of the window member is carried out.

The window member I3 is of cylindrical contour and is positioned in the opening I2 with its linear surface elements horizontal and its concaved periphery kfacing outward. Thus, it will be seen ythat if pressure is applied to, and centrally of, the inner convex surface of the window member, the latter will tend to flatten out and 'become co-planar with the front wall .II of the with the wall II along its upper and lower edge portions so as to prevent dislodgment of the window member from the opening I2. If necessary, a retaining strip (not shown) may be secured to the wall II in overlapping relation to the anges I6a of the window member.

Means are provided for dissipating static electrical charges which tend to build up on the film strip in consequence of the movement of the film strip within the casing. As here embodied, the inner face of the window member I3 is covered with a charge dissipating member I'I of electrically conductive material, -such as a thin sheet of aluminum, which is cemented thereto and is grounded in any suitable fashion, as is diagrammatically shown in vFigure 3, to the casing IU. As will appear more fully hereinafter, the charge dissipating member vI'I forms the film contacting face of the window member I3. Hence, such electrical charge as is ,accumulated by the film will be transferred thereto before it has had opportunity to 'build up to a vvalue at which it could discharge to a lower potential surface and thereby injuriously affect the film. It will `be understood that the casing I0 is in turn electrically grounded, it being customary i in the art to ground the frames of all high vtension X-ray units, or units operated in conjunction therewith. rIlhus, the flexible feed cable lto the high tensionX-ray unit (not shown) is customarily provided with a third wire `by means of which the X-ray unit is grounded back at the switchboard or `panel box from which power is taken to operate the X-ray unit. This third wire is the ground wire and is connected to the frame, usually metal, of the unit. vSuch grounding is .diagrammatically of electrical charges `which would otherwise .ac-

cumulatie onv the fum. In `addition toits charge dissipating functiomthe member I1 performs a e Vfurther functionin that it servesas a filter for ythe radiation which must-pass therethrough to the ray-sensitive material within the casing. The thickness of the material of whichthe member I1 is constituted is therefore chosen with this object in view and may be varied within relatively wide limits vdepending upon the filtering characteristics of the metal employed. In general, sheet aluminum of a thickness inthe order Ywhich an axle shaft 22 of the lm magazine I8 Vis journalled at either end and from whichthe magazine may be removed at will.

A used film magazine in the form of a spool 23 supported in brackets 24 and 2 5 at either end thereof is located in the lower portion of the casing I0.'

The spool 23 is removably' mounted in the brackets 24 and 25 and to this end the bracket 25 is formed as a hinge of which one leaf 26 is fixed to the bottom wall 21 of the casing I0. The other leaf 28 is adapted to be swung in a limited arc toward and awayfrom the spool 23 about the hinge pivot 29 and to this end its upper eXtremity is exibly connected to the side wallA 2| by a toggle 30.

The toggle 30 is suitably dimensioned so that with the hingeY leaf 28 in a substantially vertical position, the lever arms will be slightly out of axial alignment and will be in a downwardly diverging relation. In consequence, an upward pressure applied manually to the toggle `joint will cause thehinge leaf 28 to move toward the adjacent wall of the casing thereby to release the spool so that it may be removed. The hinge leaf 28 is provided intermediate its ends with .a bearing hub 3| in which a shaft 32 is journalled and is adapted to rotate the spool 23'.

The shaft 32 is vformed at its inner end with a key member 33.7which is normally received and removably lodged in a complementary keyway 34 in the adjacent e'nd of the spool 23. The opposite end of the shaft 32 carries a sheave 35 adapted to be driven in either direction by a sheave 36 carried on a shaft 31, the sheaves 35 and 36 being mechanically coupled by a crossed spring belt 38. A substantially similar driving mechanism is provided at the opposite end of the spool 23. Thus, the bracket 24 which is suitably secured at either end. to the bottom wall 21 and a sidewall 2| of the casing, is provided vwith the bearing hub 39 in which is journalled a shaft 39 having the key member 40' and sheave 4| at its inner and outer extremities, respectively, the sheave 4| being adapted to be driven by a sheave 42 on shaft 31,' the sheaves 4| and 42 .being mechanically coupled by a crossed spring belt 43.

The shaft 31 is journalled at either end in the side walls 2| and isk adapted to be manually driven from outside of the casing by suitable mechanism for the purpose provided. To this end, the shaft carries a sheave 44 which is coupled by a springy belt 45 to a sheave 46 carried b'y a shaft 41 situated inthe upper portion of the casing'and journalled at either end inthe side walls of the casmg.V

The shaft 41 carries a friction feed roller 48 concentric therewith and somewhat wider than the width of the film strip.

A gear 49 on the shaft 41 is engaged by a gear 50 secured to the inboard end of a shaft 5| which latter is journalled in a sleeve bearing 52 fixed to the side wall 2|.

The shaft 5| extends through the sleeve bearing 52 and side lwall and is provided at its outer extremity with a crank 52a by which it may be rotated at will so as to drive lm feed roller 48 and take-up spool, or reel, 23. t

An idler friction feed roller 53 is journalled on a shaft 54 which in turn is secured at its ends to a pair of rearwardly extending angularly adjustable lever arms 55. Each arm 55 is secured at its forward extremity to one of a pair of shafts 56 each journalled in one of a pair of bearing members 51 carried by the side walls 2 I.

Each larm 55 is'normally urged upwardly by one of a pair of coil springs 58 so as to cause Vthe roller 53 to press lm strip I9 between it and friction roller 48. Each spring is attached at one end to the rear extremity of one of the arms 55 and is attached at its other end to the top wall of the casing.

This film strip I9 is threaded from the spool I8 between the upper and lower lm feed rollers 48 and 53, respectively, and runs downwardly over the vertically aligned upper and lower guide rollers 59 and 60, respectively, back of the window member I3 and is secured at its leading edge to the take-up spool 23.

Thus it will be seen that as the lm crank 52a is rotated in a clockwisey direction, as viewed in Figure 1, the film strip will be drawn'from the spool IB by the lm feed rollers 48 and'53 and will travel through the exposure Yposition behind the exposure window'member I3 onto the takeup spool 23. At the same time the rotation of the shaft 41 will be transmitted via the sheave 46, lbelt 45 and sheave 44 to the shaft 31 which in turn drives the take-up spool 23 at a controlled rate through vthe belts 38 and 48 and sheaves 35, 36, 4'I and 42 so as to hold the film strip taut between the guide rollers 59 and 60. It is, therefore, apparent that the film feeding mechanism provides a positive means for feeding measured lengths of the film strip through the exposure position so that the successive measured lengths may be individually and successively exposed through the window member I3 for the making of radiographs in rapid sequence. It will be understood that the tendency of the take-up roll 23 to pull the film off the spool I8 at a faster rate than that at which the friction rollers pull the fil-m, is overcome by permitting belt 45 to slip on sheaves 44 and 46. In consequence, the film will be held taut between guide rollers 59 and 60.

Means are provided for clamping each measured length of the llm strip within the exposure area so that it will be held therein during exposure in a substantially true plane normal to the primary axis of the X-ray beam and in intimate contact with the intensifying screen. As here embodied, a clamping unit 10, whose lm clamping face is dimensioned to cover the opening I2 and/or window member I3, is suspended at its ltop on suitable anti-friction bearings for movement normal to the wall II toward and away from the window member I3 within the enclosure member.

Theclamping unit is provided adjacent its upper edge with a pair of coaxial shafts 1| each of which extends from one side of the unit toward the adjacent side wall of the casing.

Each shaft 1| is equipped at its outer extremity with a roller 12, which rests upon and is .adapted to roll back and forth upon a platform formed by one of a pair of rails 13.

Each rail 13 is secured in any suitable fashion to the adjacent side wall 2| and termina-tes at its rear extremity in an upstanding flange 1A, which serves to limit the extent of vlinear rearward travel of the rollers 12 and, hence of the clamping unit 10, in the casing. Lateral movement of the clamping unit is prevented by a pair of arms 15 each of which extendsinwardly from one of the casing side walls 2| to which it is secured in any suitable fashion, the inner .extremity of each arm terminating vin a depending flange 16 interposed between one of the rollers 12 and the clamping unit 10. Thus, it will be seen that lthe clamping unit is capable of linear movement backwards and forward in the casing.

Means are provided for actuating the clampingv unit so as to clamp the `lm strip I9 between the clamping unit and the flexible wall portion formed by the window member |3.

As here embodied, a shaft 80 extends between the side walls 2| parallel to and between the axes of the spools Hl and 23. Bearing members '8| on the opposite side walls of the casing support the shaft '80 for rotation therein, axial movement of the shaft in the bearings being prevented by thrust collars 82 which are removably attached to the shaft by set screws 83, or in any convenient fashion. The shaft '80 extends through one of the side walls and is preferably formed exteriorly of the casing as a crank '84 for rotating the shaft 80.

Means are provided for limiting the extent of angular movement of the crank arm Bil. To this `end an arcuate member 85 having an outstanding flange 86 at either vend is suitably secured to aside wall of the casing externally thereof.

A pair of toggles 90 connect the shaft 80 to the clamping unit 10, a like arm of each toggle `being iixedly secured to the shaft Sii, the other arm of each being pivotally secured to the `back of the clamping unit.

A shaft 9i is positioned vertically beneath the shaft 80 in parallel relation thereto, the shaft 9| being journalled at each end in one of a pair of bearings 92 each secured in any suitable fashion to one of the side walls 2 A pair of toggles 93 connect the shaft 9| to the clamping unit 10, a like arm of each toggle member being fxedly secured to the shaft S l, the other arm of each being hingedly secured to the back of the clamping unit.

Each pair of the toggles 90 and 93 is coupled together at the respective hinge fulcrums by one of a pair of links 94. Thus, a given angular movement of the toggles 90 will be followed by an equal angular movement of the toggles 93.

The toggles 90 and 93 and the links 94 .are so proportioned and arranged that with the clamping unit fully disengaged, and the crank` arm 84 in the neutral position as in Fig. l, the arms of each toggle will lie in downwardly divergingrela- Ation to each other so that a clockwise ,movement of the crank arm, ,as viewed in Fig. .-l, will `expand the toggles equal amounts and move Athe clamping unit toward the window member V|13. Movement of the crank arm 84 its full clockwise extent as determined by the stop member 86 should fully extend'the toggles and effect the desired clamping action.

The clamping unit 10 comprises, as is best shown in Figure 3, a backing plate |00 of plywood or other suitable lightweight material capable of preserving its shape during extended use, the front face of this plate being larger than the window member I3 and being covered with a shield member |0| preferably a layer of sheet lead of approximately 11e" thickness so as to prevent X-rays which have penetrated the film from scattering around Within the casing l0 or reaching either the fresh film or used film magazines.

A flexible mounting member |02 of resilient material, preferably sponge rubber in sheet form of approximately to 1 thickness, is cemented to the shield member |0|, the front face of the member |02 being cemented in turn to an insulating member |03 of metal, preferably aluminum in sheet form of approximately .002 thickness, serving to insulate the member |02 from an intensifying screen |04. The insulating member |03 prevents possible chemical action which would injure the intensifying screen, particularly if rubber is the material of which mounting mem-ber |02 is formed. The screen |04 is prefer'- ably attached only at its corners or edges to the insulating member |03 so as to avoid staining the screen with cement. The metal insulating member |03 is :preferably electrically grounded through the casing I0 after the manner of the charge dissipating member |1.

Means are provided for severing from the film strip when unclamped a portion thereof which has passed through the exposure position. As here embodied, a knife ,blade |I0 is reciprocably slidably mounted, for linear forward and backward movement within and horizontally of the casing I0, upon a knife table formed by a pair of brackets suitably secured to the side walls 2|.

The knife blade ||0 is suitably secured ,at each e-nd as by welding, bolting orv in any other conlvenient fashion, to one of apair of identical rack .members ||2, each slidably mounted on one of the brackets beneath one of a pair of guide members 4. Suitable means for limiting the extent of rearward movement of the rack memfbers and hence of the knife blade are provided in the form of a pair of upstand-ing lugs one of which is provided on each of the brackets The knife blade ||0 is of `sufficient length to permit it to sever any nlm strip employed in the cassette and it is located subjacent the `bottom of the clamping unit 10 so as to permit severing the film strip just below the bottom .edge of the window member I3. To this end, a knife blade ||8 is fastened to the front wall of the casing with its cutting edge horizontally disposed and parallel to the cutting edge of the knife blade I 0.

The cutting edges of the knife blades ||il and |8 are suitably beveled, positioned and arranged so `that as the blade IIE) slides across the blade ||8, the film strip will be 'horizontally severed.

Means are provided for reciprocating the knife blade ||0 from the exterior of the cassette. As hereembodied, a pair of pinion gears ||9 is fixed to a shaft |20 so that -each gear engages one of the rack members |l2, the shaft |20 being journalled at each end in one of a-pair of suitable bearing members '|2| each secured in any suitable fashion to `me of the side walls 2|.

The gears ||9 .are `adapted to be rotated tolwall I4 ofthe casing.

kgetherloy means f 'a paircf toothed sector mem'- Apair of limit members |28 extends inwardly i fromv the respective side walls 2| in coaxial alignment'and act to limit the movement of the sector members |24 in one direction and thereby limit theexten-t of vrearward travel of the knife blade H Y Each of the sector arms |26 .terminates in a bevelled vsurface portion |29 Vto be engaged by one of a pair of lever arms |30 secured to the shaft 80. Thus, by effecting counterclockwise movement of the crank arm 84, from the neutral position, as viewed in Fig, 1,'the lever arms |3il will ,be caused to press upon the sector arms |26 and rotate the sectors |24.

This clockwise movement of the sector members is transmitted through the pinion gears I9 to the rack members II2 thereby moving thel knife blade I III forwardly to. sever'the film strip.

'Thus it will be observed that as viewed in Fig. 1, the movement ofthe crank arm 84 -to sever the film strip is opposite in direction to that which moves the clamping unit 'III forwardly into clamping engagement with the film strip from the neutral :position shown in Fig'. 1. Further, it is to be observed that the lever arms |3|l are so arranged Vangularl'y that they do not contact the sector lever arms |26 until the clamping unit 'I0 has moved a substantial distance 'rearwardly wholly out. of clamping engagement with the film strip.

Means are provided for automatically restoring. therknife blade |.I to its starting position as the crank arm 84.is restored to its starting position. As here embodied, each of apair of springs nI3| Vconnects one of the sector lever ar'ms |26 ysequentially, they assist in restoring the clamping unit to its neutral position.

In operating the cassette shown in Figs'. 1 to 3, the cassette is loaded in a dark room with a roll of freshr film, the film spool IB on which the strip of film is Wound being placed'in the spool hangars 20 to which access is had by removing theV back The film strip is threadedl between the `film vfeedrolls 48 and 53,A over vguide roller 59, down- -wardly between clamping unitV 'I0 andV window 'member I3, around guide roller 60 and attached to the spool 23 preferablyby insertion in a slot orfastener customarily provided therein for that purpose. It is"essentia1 that the sensitized surface' of the filmstrip, as represented by the emulsion layer in Fig.f3, face the clamping unit sov that it will bez in contact with the intensifying screen '|04 vthereof when clamped.

The back wall 4 is now replaced and the crank 52a rotated until an unexposed Vportion ofthe film strip has been positioned in front ofthe ator'to 'determine precisely what 'length of'- the lm strip has vbeenV moved through the exposure position.

Clamping of the film in the exposure position is now effected by moving the crank arm 84 clockwise, as viewed in Figure 1, to its full extent as determined by the stop member 8S. By this operation, the clamping unit It is caused to move toward the front wall I I, first contacting the film strip I and pressing the film against the metal charge dissipating plate Il forming the inner convex face of the window member I3. Whatever static charge may have accumulated on the film during the unreeling operation preparatory to clamping is transferred through the plate I1 to the walls of the cassette from whence it'lwill be dissipated through a suitable ground as has beenhereinbefore described. Film 'injury due to the accumulation on and discharge of staticelectricity through the film is thus obviated andthe formation of hen tracks and other objectionable markings consequent upon electrical discharges is wholly avoided. It will be observed that the curvature of th window member I3 results in a progressive clamping of the film between Lthe clamping unit and window member over an area gradually increasing in magnitude in both directions from the middle line of the window member toward the top and bottom edges thereof. As the clamping pressure is increased, the Window member |3'be- Y in the art.

comes more and more planar in contour'until the clamping unit 'I0 is locked in its full forward position. At that time the portion of theV film strip in the exposure position will'be firmly h'eld n over the whole area thereof in a plane substantially normal to the .axisof the primary X-ray beam entering the opening I2. Thus, uniform sharpness may be obtainedover the whole film area in the exposure position.

The resilient member |02 serves to distribute the clamping pressure over a wider area during the clamping operation and to obtain a more uniform distribution of the 'clamping pressure during exposure thereby avoiding localized pressures of high intensities injurious to both the film and to the relatively fragile intensifying screen |84 in contact therewith. y

During exposure, the metal plate II filters the rays passing therethrough 'thereby enhancing their quality and the sharpness of the radiographic image as will be obvious to those skilled The exposure having beenfcompleted, the crank arm 84-is movedin a counterclockwise direction, as viewed in Fig. l, back to its starting position thereby releasing the film strip as the clamping unit 'ID is retracted therefrom.

The film feed crank 52a is now rotated sufficiently to position a fresh unexposed portion of be wound onto the film spool 23. Alternatively,

blade III) to move forwardly and sever the film lstrip in coaction withr the knife `blade IIB.

The spool 23 carrying the severed portion may be removed in a dark room and an empty spool 1 substituted therefor. .Substitution of a take-up spool is readily accomplished by breaking the toggle member 30 sufficiently to Withdraw the `spool winding key 30 from the spool slotV 3,4 and then substituting spools. In such case the lm strip must be reattached lto the take-up spool beforeuse.

'Referring' now more particularly to the embodiment of this invention shown in Fig. 4, the usedl'lm magazine is located externally of the casing and forms a detachable receptacle into which the exposed lm is adapted to be deposited.

A-s here embodied, the bottom wall of the casing is provided with a.l tongue |40 which is Vseated in a groove |4:| in the top of a receptacle |42.,detachably connected by suitable means (not shown) to the casing ll..

Registering slits |43 and |44 in the casing I0 and receptacle |42, respectively, are designed to permit .transfer of. the film strip from the casing |||l into'y the receptacle, the slit in the casing being located preferably slightly rearwardly of the front wall thereof so as to .be in substantial alignment with the lm as it descends between the clamping unit 10 and window member I3. A guide member |415v adjacent the slit |43 facilitates the passagey of lm through the slit. The slits |43 and |z4'4 may :be lined with velvet so as to provide light-tight openings in the known manner.

The film feeding mechanism as here embodied comprises apair of iilm feed rolls |46 and |41 actuatable from the exterior of the casing by atcrank |4 5a which may be attached to the shaft of. feed roll- |46.. The rolls |46' and |41 function toA unreel the film strip I9 from the spool I8, the llm being threaded over a pair of guide rolls |48 and |49- so as to descend between the clamping unit 10 and Window member I3, the formerbeing diagrammatically indicated for the sake of simplicity, but being inv all respectsequivalent in construction and function to the clamping unit lliy as describedv in connection with Figs. 1, 2 and 3.

Similarly, the film severing mechanism is depictedin a simplified showing, the pinion H9 beingshown as rotatable by means of a crank Y |50 which ,engages the pinion shaft |20 exteriorly oftA the casing. The receptacle |42 is preferably provided with a hinged door to permit access to its interior, the construction being such as to provide alight-tight structure. 'Ihe receptacle isof source lined with lead to render it opaque In operating the embodiment of Figure 4, the lm feeding and clamping operations are carried out just as has been described with reference to the; embodiment of Figures 1 to 3 inclusive. However, upon severance of the lm strip, the severed portion is deposited in the receptacle |42 which may be detached for processing of the lm at any convenient time, another receptacle being substituted therefor so thatthe making of the radiographsmay proceed with a minimum of interruption- This construction Vpossesses the obviousv advantage that the casing HJ need not be removed and carried tothe dark room in order thatthe-severed portion of the-film strip may be taken out for processing. In consequence,` it lends itself to operations where'time is at a premmm.

It will beunderstood that fora permanent installation the front-wall of the casing lliv and` receptacle |42 may, if desired, form a part of a darkroom wall againstwhich the X-ray beam is projected. In such case, the receptacle |42 need notn be detachable, but may be permanently secured to or form a part-of the casing l0 and the wall. Severed. portions of thev lm strip may :be deposited and contained in the receptacle pending their removal bythe darkroom operator for processing.

The invention in its broader aspects is not limited to the specific mechanisms shown andv describedl but departures may be made therefrom Within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

What I claim is:

1. A cassette for X-ray radiography with provision for' handling and exposing successive portions of. a long strip ofray sensitivefmaterial, the cassette comprisinga. casing having a curved flexible wall'. portion forming an X-ray permeable exposure window; clamping means within said casing movable intoiandi out4 of a. predetermined position for pressing a' measured length of said strip into substantially planar engagement with said wall portion. for: exposure to X- rays through said4 window; and, means within said casing operable upon movement of said clamping means out ofA said predetermined position, for severing said strip.

2. A cassette for X-ray radiography withy provision for handling and exposing successive portions of a long strip of `ray-sensitive material, the cassette comprising a casing having. an opening;` a` flexible member of substantially cylindrical contour forming an X-ray permeable exposure window in said. opening; and, clamping means within said casngmovable into and out of a predetermined position forV pressing a measured length of said strip into substantially planar engagement withv said member for exposure to X-rays through said window; and, means within said casing operable upon movement of said clamping means' outv of said predetermined position, for severing said strip.

3.. A cassette for X-ray radiography with pro-- vision for handling and exposing successive portions: of a longstrip` of ray-sensitive material, the cassette comprising a casing having a curved flexible. wall portion'Y faced with electrically conductive ray ltering material and forming an X-ray permeable exposure window therein; clamping means within said casing movable into and out of a predetermined position for pressing a measured length of said strip into substantially planar engagement With said wall portion for exposure to X-rays filtered through said window; and, means within said casing operable upon movement of said clamping means out of said predetermined position, forv severing said strip.

4. A cassette for X-ray radiography' with provision for handling and exposing successive portions of a long strip of ray-sensitive material, the cassette comprising a casing having a 'curved flexible wall portion forming an X-ray permeable exposure window therein; lm spools within the casing; means including a handle externally of said casing for winding measured lengths of said strip from one ofsaid spools past said window onto the other of saidspools; clamping means within said casing including an intensifying screen movable into and out: of a. predetermined position for pressing a measured length of said strip into substantially planar engagement with said Wall portion for exposure to X-rays through said exposure window; means within said casing operableupon movement of said clamping means out of said predetermined position, for severing including a member externally of said casing.

5. A cassette for X-ray radiography with provision for handling and exposing successive portions of a long strip of ray-sensitive material, the

cassette comprising a casing having a Wall portion forming an X-ray permeable exposure window therein; means forming Va used lm magazine removably associated with said casing; a film spool within said casing upon which said strip is Wound; means actuable from the exterior of said casing for transferring measured lengths of said strip from said spool past said window to said magazine means; clamping means Within said casing movable into and out of a predetermined position for pressing a measured length of said strip into substantially planar engagement With said Wall portion for exposure to X-rays through said Window; and, means actuable from the exterior of said casing and oper-V able upon movement of said clamping means out of said predetermined position, for severing said strip. I

6. A cassette for X-'ray radiography with provision for handling and exposing successive portions of a longstrip of ray-sensitive material, the cassette comprising a casing having a wall portion forming an X-ray permeable exposure Window therein; a receptacle forming a used nlm magazine detachably connected to said casing; a'spoo'l Within said casing upon which said strip is Wound; means for Winding measured lengths rof said strip from off said spoolpast said Window into said receptacle; clamping means Within said casing movable into and out of a predetermined position for pressing said strip into substantially planar engagement With said Wall portion for exposure to X-rays through said Window; and, means Within said casing operable upon movement of said clamping means out of said predetermined position, for severing said strip.

7. A cassette for X-ray radiography with provision for handling and exposing successive lengths of a long strip of ray sensitive material, the cassette comprising a casing having an X-ray permeable exposure window therein; clamping means including an intensifying screen Within said casing, said clamping means being movable into and out of a predetermined position for pressing a length of said strip against said Window and into intimate contact with said screen for exposure lto X-rays through said window;

and, means Within said casing operable upon movement of saidrclamping means out of said predetermined position,- for severing said strip.

8. A cassette for X-ray radiography with provision for handling and exposing successive lengthsrof a long strip of ray sensitive material; the cassette'comprising a casing having an X-ray permeable exposure Window faced with electrically conductive ray filtering material; clamping means Within said casing movable into and Vout of a predetermined position for pressing a length of said strip into engagement with said ray ltering material for exposure to X-rays ltered through said window and dissipation of electrical charges from said strip through said ray filtering material; and, means within said casing operable upon movement of said clamping means out of said predetermined position, for severing said strip.

9. A cassette for X-ray radiography with provision for handling and exposing successive portions of a long strip of ray-sensitive material, the cassette comprising a casing having an X-ray permeable exposure Window therein; meansforming a used hn magazine removably associated With said casing; a lm spool Within said casing upon which said strip is Wound; means actuable from the exterior of said casing for transferring measured lengths of said strip from said spool past said window to said magazine means; clamping means Within said casing movable intov and out of a predetermined position for pressing a measured length of said strip into intimate contact with said window for exposure to X-rays through said Window; and, means actuable from the exterior of said casing and operable upon movement of said clamping means out of said predetermined position, for severing said strip.

10. A cassette for X-ray radiography with provision for handling and exposing successive lengths of a long strip of sensitized material, the cassette comprising a casing having an X-ray permeable window therein; Winding reels within the casing; means for winding said strip 01T one reel and onto the other past said Window for exposure to X-rays therethrough; means for clamping a length of said strip for exposure to X-rays through said Window and means Within said casing for severing a length of said strip after passage through the exposure position, from the remainder of said strip.

FRANK T. POWERS. 

